Diagnostic challenges in pediatric-onset multiple sclerosis: a case report

Background: Pediatric-onset multiple sclerosis (POMS) is a rare disorder mostly diagnosed during adolescence; however, disease onset can occur before the age of ten. Differentiating POMS from other acquired demyelinating syndromes (ADSs) is challenging, especially after the first demyelinating event. Here we present the case of a 7-year-old boy with prior learning disability, who was diagnosed with POMS, but only after his third demyelinating event. This case is particularly interesting due to the presence of several atypical demographic and overlapping clinical, radiological and laboratory features of ADS. Case Description: A 7-year-old boy presented with a 5-day history of nausea, vomiting, gait instability, strabismus in the left eye, head tilting to the left and signs of encephalopathy with positive oligoclonal bands (OCB) and multiple demyelinating lesions in the brain on magnetic resonance imaging (MRI), leading to a diagnosis of acute disseminated encephalomyelitis (ADEM). The patient was treated with methylprednisolone (MP) pulse therapy and symptoms resolved. He experienced a second episode with complaints of vertigo and diplopia with suspected encephalopathy; however, OCBs were negative, resulting in a diagnosis of multiphasic ADEM. Finally, after a third demyelinating event that occurred without encephalopathy, the patient was diagnosed with POMS. Disease-modifying therapy was initiated with glatiramer acetate, which was discontinued due to frequent relapses and switched to rituximab. Patient had an anaphylactic reaction to rituximab but has now been relapse-free for over two years on natalizumab. Conclusions: Early recognition of POMS is crucial, yet remains a significant problem in younger patients. Delayed POMS diagnosis remains a significant issue, and efforts to reduce the time to diagnosis are essential for early disease-modifying treatment initiation to improve long-term prognosis and reduce disability.